If you can include a wad demonstrating the problem, please do so. Bug reports that include fully-constructed demos have a much better chance of being investigated in a timely manner than those that don't.

Please make a new topic for every bug. Don't combine multiple bugs into a single topic. Thanks!

If I define textures to be scaled down in the TEXTURES lump, and offset them in a map, the offsets are applied incorrectly in the softplanar and OpenGL renderers. The softpoly renderer seems to work just fine for some reason.

You have to add a 'worldpanning' instruction to each definition. The reason for this lies deep in the past. When texture scaling was originally implemented it was done with per texel panning, not world-unit panning. Needless to say that isn't the most useful thing, but when a decision had to be made what to use as default, the bad option was chosen.